Acute and Subacute Toxicity of Sialidase From Type A in Mice (): Organ-Specific Damage and Immune Response.

Sialidases, enzymes produced by Type A, play a critical role in cleaving sialic acid residues essential for viral entry into host cells. By targeting pathogens such as coronaviruses, influenza, and paramyxoviruses, sialidase represents a promising therapeutic candidate. While in vitro studies confirm its efficacy against influenza, evaluating its safety profile in vivo is imperative. This study investigates the acute and subacute toxicity of sialidase from Type A in BALB/c mice (). Acute toxicity involved a single intranasal dose followed by a 14-day observation, while subacute toxicity encompassed daily doses for 30 days. Mice were administered 187.5, 375, or 750 mU/mL of sialidase, with saline as the control. No mortality or overt toxicity occurred, but significant histopathological alterations were evident in the lungs and liver at higher doses. Observed effects included lung inflammation and edema, liver congestion, and kidney inflammation. Hematological analysis revealed immunosuppressive effects, including reduced white blood cell and lymphocyte counts, alongside dose-dependent IL-6 expression changes. Sialidase doses of 187.5 and 375 mU/mL were deemed safe, whereas toxicity became pronounced at 750 mU/mL.